import java.util.*;
public class 树图存储 {
    static int N=100010,M=N*2;
    static int h[]=new int[N],e[]=new int[M],ne[]=new int[M],idx;
    public static void main(String[] args) {
        Arrays.fill(h, -1);
    }
    static void add(int a,int b){
        e[idx]=b;
        ne[idx]=h[a];
        h[a]=idx++;
    }
}
